Software Engineer

La Fosse; España; Remote; EUR 112,000 - 156,000; Full time

Job summary

La Fosse is seeking an experienced Senior Ruby on Rails Engineer to support a platform modernisation and systems integration project. The role emphasizes backend development, system architecture decisions and reliable delivery in a fully remote European setting.

You will design and implement scalable backend services, assess current architectures, and lead migration initiatives while collaborating with distributed teams.

Qualifications

• Experience designing and implementing Ruby on Rails applications in production environments.
• Strong understanding of system architecture and backend service design.
• Proven ability to lead complex integration projects and migrations.

Responsibilities

• Design, develop and maintain scalable backend apps with Ruby on Rails.
• Assess systems and identify opportunities to improve architecture and performance.
• Lead planning and implementation of system modernisation and migrations.

Skills

Ruby on Rails

System architecture

Backend development

REST APIs

Cloud infrastructure

Data migrations

AI-assisted tools

Distributed teams

Performance optimization

Integrations

Tools

AWS

GitHub Copilot

Claude

Job description

Senior Ruby on Rails Engineer - Platform Modernisation & Systems Integration

Location: Fully Remote (Europe)

Contract Duration: 3 Months

Start Date: ASAP

About the Opportunity

We are looking for an experienced Senior Ruby on Rails Engineer to support a business-critical platform modernisation and systems integration project.

This is a hands-on technical role with a strong emphasis on system architecture, backend development and complex integrations. The successful candidate will help improve existing systems, modernise technical infrastructure and ensure reliable integration between applications and services.

The role requires someone who can understand complex existing codebases, make sound architectural decisions and take ownership of technical delivery.

Key Responsibilities

• Design, develop and maintain scalable backend applications using Ruby on Rails.
• Assess existing systems and identify opportunities to improve architecture, performance and maintainability.
• Lead technical planning and implementation of system modernisation and migration initiatives.
• Design and implement integrations between internal platforms and third-party services.
• Support data migration, transformation and integration activities.
• Ensure data integrity, system reliability and consistency across applications.
• Identify technical risks, dependencies and potential integration challenges.
• Collaborate with engineering teams and stakeholders to define appropriate technical solutions.
• Use modern development practices and AI-assisted tools to support code quality, testing and delivery.
• Take ownership of technical deliverables and work independently within a remote engineering environment.
• Strong commercial experience developing production applications using Ruby on Rails.
• Proven experience designing and architecting complex backend systems.
• Strong understanding of REST APIs, system integrations and backend services.
• Experience working with established or legacy codebases.
• Solid understanding of relational databases, particularly PostgreSQL or MySQL.
• Experience delivering system migrations, platform improvements or complex integration projects.
• Strong knowledge of software design principles, performance optimisation and maintainable architecture.
• Ability to troubleshoot complex technical issues and make independent architectural decisions.
• Strong communication skills and the ability to work effectively within distributed teams.
• Experience with SaaS platforms or enterprise software applications.
• Exposure to billing, subscription management or financial systems.
• Experience with data migrations and reporting integrations.
• Knowledge of webhooks, background processing and asynchronous systems.
• Experience with cloud infrastructure, particularly AWS.
• Familiarity with CI/CD pipelines, automated testing and modern development practices.
• Experience using AI-assisted development tools such as Claude, GitHub Copilot or similar technologies.

What We're Looking For

We are particularly interested in engineers who combine strong Ruby on Rails expertise with a broader understanding of system architecture and technical delivery.

The ideal candidate will have experience taking ownership of complex engineering projects, improving existing systems and delivering reliable technical solutions.

This opportunity would suit a senior engineer who is comfortable working independently, navigating technical complexity and contributing to architectural decisions rather than focusing exclusively on feature development.